With regard to insulin 3 companies control 90% of worldwide production. I'm not aware of a third party manufacturer that can actually produce modern insulins at scale. Even if they existed, they still have to work around the issues previously stated. It is unlikely that you would be able to partner with the big players as they have no incentive to help a competitor and they are already running at full capacity. You probably don't have any other option than to build it yourself.

Medical devices are frankly a lot simpler than making new drugs. (I know they are still exceptionally challenging)